1. Field of the Invention
The present invention generally relates to a PC (Personal Computer) Card slot and, more particularly, to a PC Card slot provided with a lock mechanism (or structure) for preventing a PC card from unintentionally coming or falling off the slot owing to a shock (or vibration), a malfunction and so forth.
2. Description of the Prior Art
In recent years, there has been striking reduction in size, weight, thickness and power consumption of electronic equipment. Especially, the size and weight of the personal computer have decreased markedly with the development thereof from the desktop computer through the laptop computer to the notebook computer. Further, in addition to these, new small information (processing) devices, such as a handwriting information (processing) device which is excellent in portability, have emerged.
In such a field, PC cards, such as an IC memory card obtained by packaging a semiconductor memory on a credit-card-sized card highly densely, and an I/O card, attract attention as media for information interchange. As compared with magnetic recording media such as a floppy disk and a hard disk, such PC Cards have the following outstanding merits.
(1) PC Card eliminates the need for a driver unit, so that the reduction in size and weight of the device can be achieved.
(2) PC Card can operate at a low voltage of 3 volts or so, with the result that a long battery-driven operation can be achieved and that there can be provided a device which excels in portability.
(3) High-speed access to the device can be realized.
(4) PC Cards excel in what is called "environment-proof". Ranges of allowable temperature and moisture thereof are wide. Moreover, PC Cards are vibration-proof and shock-resistant.
(5) Media can be easily carried. This allows data exchange to be achieved. Thus, PC Cards are superior in potability.
(6) PC Cards can be loaded with various semiconductor memories such as ROM and RAM.
Such PC Cards are classified into three types by thickness thereof. Usually, PC Cards having a thickness of 3.3 mm are classified as Type I. Further, PC Cards having a thickness of 5.0 mm is classified as Type II. Moreover, PC Cards having a thickness of 10.5 mm is classified as Type III.
Furthermore, PC Cards acting as memory cards are used as add-on (or add-in) memories, or used like HDs (namely, Hard Disks) or FDDs (namely, Floppy Disk Drivers (or Drive units)). On the other hand, usually, PC Cards acting as I/O cards are not used singly. Such a PC Card is used by being connected with an accessory or by being connected to another device through a cable or the like. PC Cards of major kinds are a LAN card, a FAX/MODEM card and a PCM sound card.
Currently, notebook personal computers and handwriting information (processing) devices, which are provided with what are called PC Card slots so as to be equipped with such PC Cards, respectively, are provided on the market by many makers.
Hereinafter, a conventional PC Card slot 41 will be described by referring to FIGS. 20 to 27. The conventional PC Card slot is formed in such a manner as to be able to be equipped with two PC Cards 2. FIG. 20 is a plan view of the conventional PC Card slot 41. FIG. 21 is a front view of the conventional PC Card slot of FIG. 20. FIG. 22 is a left side view of the conventional PC Card slot of FIG. 20. FIG. 23 is a right side view of the conventional PC Card slot of FIG. 20. FIG. 24 is a sectional view taken on line XXIV--XXIV of FIG. 20.
Further, FIG. 25 is a plan view of the conventional PC Card slot 41 into which a single PC Card 2 is fit. FIG. 26 is a front view of such a conventional PC Card slot 41. Moreover, FIG. 27 is a plan view of the conventional PC Card slot 41 from which the PC Card 2 is released.
In the case of the conventional PC Card slot 41 illustrated in these figures, a slot main body 42 is divided into two stages (namely, upper and lower stages), namely, an upper slot main body 42 and a lower slot main body 42 in such a manner that two PC Cards 2 of Type I or Type II can be fit thereinto. Each of these slot main bodies 42 is constituted by thin plates made of metallic materials such as steel. Further, cavities, into which PC Cards 2 are inserted, are formed by bending these thin plates. Thus, the aforementioned slot main bodies 2 serve as guides each for guiding the aforesaid PC Card 2 thereinto when inserting the aforesaid PC Card 2 into the aforementioned cavity.
Moreover, an upper connector 43a and a lower connector 43b are provided in these upper and lower slot main bodies 42, respectively. These connectors 43a and 43b have roles in positioning the PC Cards 2 and in electrically connecting each of the PC Cards 2 with a wiring board 44. Namely, each of these connectors 43a and 43b is provided at the rear of the corresponding slot main body 42 in such a way as to extend from the left end to the right end thereof. Furthermore, two rows (namely, upper and lower rows) of pin terminals are embedded in a front-side portion of the PC Card slot 41 as illustrated in FIG. 21. Additionally, as shown in FIGS. 22 through 24, the wiring board 44 is supported and sandwiched between the upper connector 43a and the lower connector 43b in such a manner as to protrude from therebetween toward the back of the wiring board 44. Further, the aforementioned pin terminals 45 are fit into two rows (namely, upper and lower rows) of fitting holes (not shown) formed in the PC Card 2 to thereby hold the PC Card 2. In this way, basically, the PC Card 2 is fixed to the slot by a fitting force acting between the PC Card 2 and a set of the pin terminals 45. Moreover, as illustrated in FIG. 24, the aforementioned pin terminals 45 are electrically connected to and a cable terminal (not shown), which is electrically connected to the main unit (not shown) of the device, is coupled to the aforesaid wiring board 44. Therefore, each of the aforementioned PC Cards 2 is connected to the main unit of the device through the pin terminals 45, the wiring board 44 and the cable terminal in sequence.
A releasing lever for canceling (namely, releasing the PC Card from) the fitting force acting between the PC Card 2 and the set of the pin terminals 45 of the connector 43 is rotatably journalled in a corresponding one of the main bodies 42 between each of the connectors 43 and the corresponding one of the slot main bodies 42. Let reference characters 46a and 46b denote an upper releasing lever, which corresponds to the upper slot main body 42, and a lower releasing lever, which corresponds to the lower slot main body 42, respectively. Each of these releasing levers is formed so that the length thereof is nearly equal to the distance between the left and right edges of each of the aforementioned slot main bodies 42. One end portion (incidentally, this end portion is the left end portion in the case of the upper releasing lever 46a of FIG. 20, and is the right end portion in the case of the lower releasing lever 46b) of each of the releasing levers 46a and 46b is formed as a projection portion 47 protruding from the slot main bodies 42. The other end portion (incidentally, this end portion is the right end portion in the case of the upper releasing lever 46a of FIG. 20, and is the left end portion in the case of the lower releasing lever 46b) of each of the releasing levers 46a and 46b is formed as an abutting portion 48 adapted to abut against an edge portion of the PC Card 2 when held in a corresponding one of the slot main bodies 42.
A lever operating stick 49 is attached to the aforementioned projection portion 47. Further, an operating knob 50 is attached to an operated-side end portion (namely, a lower end portion as viewed in FIG. 20) of this lever operating stick 49. This lever operating stick 49 is held by holding clicks 51 and is adapted to be able to make reciprocating motion back and forward.
Therefore, in the case that the aforementioned PC Card 2 is fit into the PC Card slot 41, the abutting portion 48 of the aforementioned releasing lever is pushed by the edge portion of the aforementioned PC Card 2 and is turned counterclockwise, as illustrated in FIG. 25. Thus, the aforementioned lever operating stick 49 is slid downwardly as viewed in this figure. Further, the aforementioned PC Card 2 is fit into a corresponding one of the aforesaid slot main bodies 42 by coupling the aforementioned PC Card 2 with the pin terminals 45 of the aforesaid connector 43.
In contrast, when removing the aforementioned PC Card 2 from the PC Card slot 41, the operating knob 50 of the aforementioned lever operating stick 49 is pushed and is thus turned clockwise, as illustrated in FIG. 26. Thus, the edge portion of the aforementioned PC Card 2 is pushed by the projection portion of the aforementioned releasing lever by utilizing what is called the principle of a lever (namely, utilizing leverage). Consequently, the fitting force acting between the aforementioned PC Card 2 and the aforesaid pin terminals 45 is released, and the PC Card 2 is removed from the corresponding one of the aforementioned slot main bodies 42.
Meanwhile, PC Card slot 41 as above described is frequently used in portable devices which highly frequently undergo shocks and vibrations in comparison with ordinary desktop (or tabletop) devices. Thus, such portable devices need to be provided with a coming-off preventing lock mechanism for preventing a PC card from easily coming off a PC Card slot.
However, there is no conventional PC Card slot 41 formed in such a manner as to be integral with a coming-off preventing lock mechanism. Further, the lock mechanism is provided in the device separately from the PC Card slot 41.
Thus, the operating knob 50 is placed separately from the lock mechanism, so that the operability of the conventional PC Card slot is low. Further, the conventional PC Card slot has encountered a problem in respect of efficiency in assembling the device.
Moreover, an operation of the operating knob 50 is performed separately from (or independently of) that of the lock mechanism, so that users have easily forgotten to lock and unlock (namely, release the lock). Therefore, when forgetting to lock the lock mechanism, there are fears that the PC Card 2 is easy to come off the slot 41 owing to vibrations and shocks and thus, needless to say, an operation failure of the PC Card 2 is caused, and that this causes what is called a system error of the main unit of the device, or that at the worst, electronic parts provided in the PC Card 2 are damaged. In contrast, when operating the knob 50 without releasing the lock of the lock mechanism, an excessive force is applied to the releasing lever. Thus, there is a fear that the PC Card slot 41 itself is destroyed.
Furthermore, the conventional PC Card slot 41 has problems in that if the PC Card slot 41 is placed in the inner part of the device so that the end portions of the PC Card 2 do not project from the device during the PC Card 2 is fit thereinto, the operating knob 50 is also placed in the inner part of the device and thus becomes difficult to operate, and in that if large space is taken up in the vicinity of the operating knob 50 so as to improve the operability of the knob 50, the size of the device becomes large inconveniently.